Martha Stewart is not the richest person on our list of the 25 most transformative icons, rebels and leaders of the past quarter-century. She has not created the most wealth or employment for others. Nor does she have the greatest global reach. But she embodies many of the defining innovative characteristics of U.S. business in the past 25 years: reinvention, the second act, the personality-based brand and the explosive post-1980s growth of homemaking as a media and retailing category. In an era of tumultuous technological and economic change, Stewart has built a powerfully appealing American brand around idyllically well-organized, simple and tasteful domestic life.

A home-based catering business that Stewart started in her mid-30s eventually led to a series of successful cookbooks in the 1980s and a TV career. In 1990, Time developed a magazine, "Martha Stewart Living," for her. That was followed within a couple of years by a companion weekly TV show that became daily. In 1997, Stewart bought out the media and merchandising ventures bearing her name and gathered them into her own company, Martha Stewart Living Omnimedia, with her business partner, Sharon Patrick, as chief operating officer.

Martha Stewart stamps her brand on homemaking

She built a powerfully appealing American brand around idyllically well-organized, simple and tasteful domestic life in an era of tumultuous change.

They took the company public in 1999, making Stewart on paper the first female self-made billionaire in the U.S. She lost her billionaire status in the dot-com recession, though, and did not appear on Forbes' billionaires list until 2006, two years after eBay's Meg Whitman made her debut and a year after Stewart was released from jail.

She had served five months after being convicted on charges of conspiracy and making false statements to investigators in connection with the 2001 sale of 3,928 shares of ImClone Systems stock after receiving insider information from her broker at Merrill Lynch. The day after the sale, the stock fell 16 percent.

Her settlement of a related civil case with the Securities and Exchange Commission included a five-year restriction (starting in 2006) on her serving as a director or a financial officer of a public company, though she was able to continue as MSLO's chief creative officer, the title she took after stepping down as chair and CEO when her legal troubles started in 2003.

Her highly publicized comeback was based on a syndicated daytime TV show and a one-season spin-off of "The Apprentice," a reality talent show starring Donald Trump on NBC. The media blitz was bolstered by a $30 million deal for a channel on Sirius Satellite Radio, as well as a slew of new books.

Stewart has always combined undisputed talent, drive, her celebrity and a formidable work ethic to carry her through bad times. She expanded her merchandising business—which at the time consisted of $1 billion in annual sales of Martha Stewart housewares at Kmart stores—adding deals with Macy's and home builder KB Home. In 2012, Macy's claimed that a deal to sell Martha Stewart-branded products in in-house boutiques in J.C. Penney stores violated its exclusive agreement with her. The dispute has since been settled.

Stewart's company has struggled financially since the start of her legal troubles. Its market valuation of $157 million in 2013—a year in which it lost $1.8 million—is barely a 10th of its market cap when it went public in 1999. CEO Dan Dienst is a turnaround specialist. But with the SEC's ban over, Stewart is back on MSLO's board as nonexecutive chair and shows no sign of slowing down. Martha Stewart the company, Martha Stewart the brand and Martha Stewart the person are inseparable.